نوع مقاله : علمی-پژوهشی
نویسندگان
1 دانشکده مهندسی برق، گروه مخابرات، دانشگاه صنعتی شیراز، شیراز، ایران
2 گروه مخابرات، دانشکده مهندسی برق، دانشگاه صنعتی شیراز، شیراز، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
In this paper, a design procedure is presented for design of tunable coding metasurface for beam controlling applications in terahertz frequencies. The designed unit cell is a graphene-based structure consisting of individual ribbons that can be independently biased. As a result, a two-bit structure with phase difference between adjacent states is obtained, which is used in the implementation of two controllable metasurfaces with beam steering and shaping abilities. The simple shape of the proposed unit cell is an important benefit for practical implementation of the metasurface. Moreover, the equivalent circuit model of the unit cell is presented to better understand the performance of graphene ribbons. In the reflection response of the cell and in the frequencies between 1.3 to 1.55 THz, the phase difference of with an error less than is kept between adjacent states while the normalized amplitude is between 0.74 to 0.87 in the desired frequency band. A theoretical method based on the generalized Snell's law has been used to verify the validity of the full-wave simulation results. The refraction angle of the beam in the first metasurface may be controlled by changing the phase difference along x and y directions of the metasurface. This subject requires the use of lattices with different dimensions. The reflected angle of beam varies in the range of 9 to 25 degrees with changing the size of lattice. In the second metasurface the cells are arranged in such a way that a vortex beam with l=+1 is obtained.
کلیدواژهها [English]
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